Euryarchaeota (from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

''εὐρύς'' eurús, "broad, wide") is a phylum of archaea. Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines,

halobacteria Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. Halobacteria are now recognized as archaea rather than bacteria and are one of ...

, which survive extreme concentrations of salt, and some extremely

thermophilic A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C. They are separated from the other archaeans based mainly on

rRNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosoma ...

sequences and their unique DNA polymerase.

Description

The ''Euryarchaeota'' are diverse in appearance and metabolic properties. The phylum contains organisms of a variety of shapes, including both rods and

cocci A coccus (plural cocci) is any bacterium or archaeon that has a spherical, ovoid, or generally round shape. Bacteria are categorized based on their shapes into three classes: cocci (spherical-shaped), bacillus (rod-shaped) and spiral ( of whi ...

. ''Euryarchaeota'' may appear either

gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bact ...

or gram-negative depending on whether

pseudomurein Pseudopeptidoglycan (also known as pseudomurein;White, David. (1995) ''The Physiology and Biochemistry of Prokaryotes'', pages 6, 12-21. (Oxford: Oxford University Press). . PPG hereafter) is a major cell wall component of some Archaea that differs ...

is present in the cell wall. ''Euryarchaeota'' also demonstrate diverse lifestyles, including methanogens, halophiles, sulfate-reducers, and extreme thermophiles in each. Others live in the ocean, suspended with plankton and bacteria. Although these marine euryarchaeota are difficult to culture and study in a lab, genomic sequencing suggests that they are motile

heterotroph A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

s. Though it was previously thought that euryarchaeota only lived in extreme environments (in terms of temperature, salt content and/or pH), a paper by Korzhenkov et al published in January 2019 showed that euryarchaeota also live in moderate environments, such as low-temperature acidic environments. In some cases, euryarchaeota outnumbered the bacteria present. Euryarchaeota have also been found in other moderate environments such as water springs, marshlands, soil and

rhizosphere The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. Soil pores in the rhizosphere can contain many bacteria and other microo ...

s. Some euryarchaeota are highly adaptable; an order called

Halobacteriales In taxonomy, the Halobacteriales are an order of the Halobacteria, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated ...

are usually found in extremely salty and sulfur-rich environments but can also grow in salt concentrations as low as that of seawater 2.5%. In rhizospheres, the presence of euryarchaeota seems to be dependent on that of mycorrhizal

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

; a higher fungal population was correlated with higher euryarchaeotal frequency and diversity, while absence of mycorrihizal fungi was correlated with absence of euryarchaeota.

Phylogeny

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the nomenclature, naming and Taxonomy (biology), taxonomy of prokaryotes, following the taxonomy requirements and rulings of the In ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...

(NCBI) A third phylogeny, 53 marker proteins based

GTDB The Genome Taxonomy Database (GTDB) is an online database that maintains information on a proposed nomenclature of prokaryotes, following a phylogenomic approach based on a set of conserved single-copy proteins. In addition to breaking up parap ...

07-RS207.

References

External links

Comparative Analysis of Euryarchaeota Genomes
(at DOE's IMG system)`1 {{Taxonbar, from=Q204219 Archaea phyla

Description

Phylogeny

See also

References

Further reading

External links